(1) Field of the Invention
The present invention relates to an apparatus for controlling the flowpath area in a gas turbine engine. More specifically, the present invention relates to an apparatus for adjustably controlling the flowpath area of a gas turbine engine through the use of rotationally mounted vane components.
(2) Description of the Related Art
When operating gas turbine engines, it is frequently desirable to control the amount of gas flowing through the secondary flowpath between the outer duct and the inner support structure. One common method of achieving such control is to install an apparatus for adjusting the area through which the gas may flow. It is most desirable for such an apparatus to provide for complete blockage of gas flow when necessary while causing little if any blockage when needed. Typically, an attempt to maximize the efficiency of either of these constraints results in a diminution in the efficiency of the other.
What is therefore needed is an apparatus, and method for so using, for controlling the flowpath area in a gas turbine engine which provides both near total blockage of gas flow and virtual unimpeded flow of gas when desired.